Strop mounting



Patented Dec. 23, 1941 UNITED STATES PATENT OFFICE STRQP MOUNTINGApplication June-21, 1939,. SerialNo. 280,235

2 Claims.

Thisv invention relates in general to strop mountings: and moreparticularly to a strop mounting whiohis adapted to'have a plurality ofSfiIOps mounted thereon in tensioned' relationship.

A principal object-of the invention is the provision ofa strop mountingwhich is simple in design and construction and is adapted to provide auniform. tension to aplurality of strops simultaneously withoutlessening the effectiveness of either of thestrops.

An important object of the invention isthe provision of. a'strop.mounting adapted to be used in stroppingMiorotome knives with a minimumamount of" efiort being necessary to obtain the best." results.

In: stroppingMicrotome knives, it is always advisable tousertwo' or morestrops, one strop having itsasu-rface impregnated with an. abrasivesubstance; such: as. diamond. dust, or the like, for sharpeningtheedgei'of the knife and a second strop adapted to provide a finish to theedge and remove any rough. surfaces formed in the edge. An importantobject. of the invention, therefore, is the, provision. of a strop.mounting having two strops mounted thereon under aiuniform tension, thestrops and the tensioning unit upon which they are mounted being adaptedto be rotated so that either of the two strops are available forimmediate use by merely rotating the tensioning unit until the desired.strop is brought into operativeposition.

Another important object of the invention is the provision of" a stropmounting having two or more strops mounted thereon under tension which:is applied by means of. a screw, the latter, after it is tightened,remaining fixed and; requiring no further adjustment, thus allowingtheuse of. both hands to control the knife or razor.

Numerous: other: objects and advantages of the invention will beapparent as it is better understood from the following description,which, when taken in connection with the accompanying drawing, disclosesa preferred embodimen thereof.

In the drawing,

Figure l is a perspective view of the mounting illustrating the strapsin tensioned position;

Figure 2 is an enlarged top plan View of the mounting, with the centerportion of the tensioning unit and strops broken away;

Figure 3 is a vertical sectional view of the mounting takensubstantially on the line 3--3 of Fig. 2; and

Figure 4 is a detail sectional view of the tenunit [5.

sioning unit taken substantially on the line 4-4 of Fig. 2.

Referring more particularly to the drawing; reference numeral llindicates in general a stand portion, which maybe formed as an aluminumcasting. or from any other suitable material, and comprises a baseportion 12 and two upright sup porting members I3 and I4.

Rotatably mounted between the supports I3 and I4 is a tensioning unit,indicated generally byreference numeral lb. The unit I5 comprises twomembers Hi and I! which are mounted upon the stand. I I as an integralunit between the supports: I3and M. The member i6 is usuallymade as analuminum casting, but may be formed in any other suitable manner, andhas a head portion I;8: at one end which is considerably larger than themain body portion ofthe memben' Extending outwardly from. the endportion I8 is a protuberance l9 in which a stud 2'! is fastened'in any'suitable manner, such as by a pin 22, or the like. The stud 21; extendsthrough an aperture 23 formed in the support" I3, and is held securelyin place by a wing nut 24. Positioned between the nut 24' and thesupport. I3 is a lock washer 25 which, together with the wingnut 24,locksthe member N5 in any desired position, when the nut 24- is screwedup tightly on the stud 2|.

An elongated slot 26 is formed in the member H5: at the end opposite thehead portion 18, and inwardly extending" tongues 21 are provided on theside surface of: this slot'which are adapted to slidably engage incorresponding grooves 28 formedin the outer side surfaces of the memberH, so that the unit 15. may be lengthened or shortened by the operatoras desired. The member IT has a head portion 29 which is similar in.size and shape to the head portion l8 ofthe member l6; Extendinglongitudinally through the center of the member I! is an aperture 3|.The aperture 3| is internally screw-threaded for 'a short distance atthe end oppositeto the head portion 291 and is adapted to receive thethreaded portion 32 of an elongated bolt 33. The bolt 33 extends throughand is journalled in an aperture 34 formed in the support 14, and hasasuitable head member 35 formed integrally therewith or fastened theretoat its outer end to facilitate rotation thereof. The threaded portion 32of the bolt 33 abuts against the inner end 36 of the slot 26 so that, asthe bolt 33 is turned in a clockwise direction (Figs. 2 and 3), themember I! will move to the right or outwardly relative to the member Hito extend the effective length of the Conversely, when the bolt 33 isturned in a counter-clockwise direction, the member I! will be moved tothe left and the unit [5 will be shortened accordingly.

A pair of strops 31 and 38 are removably mounted upon the unit 15 bymeans of a plurality of eyelets 39 formed adjacent the ends thereofwhich are engageable over small studs 4| rigidly secured .in anysuitable manner to the outer curved surfaces of the head portion I8 and29. As pointed out above, when the bolt 33 is tightened, the effectivelength of the unit I5 will be increased, and this lengthwise adjustmentof the unit l5 may be selectively varied to place the desired tensionupon the strops 31 and 38,

The stand II has small rubber cushions or feet 42 mounted on the lowersurface of the base I2 to provide a firm footing and to prevent thestand from moving about when the device is being used. Although thedevice as a whole is portable, the stand H is made sufficiently heavy toaccomplish this result.

An extremely sharp knife is necessary in laboratories to out thin slicesfrom a specimen, so that the same may be placed under a microscope fordetailed examination. These knives are usually special knives calledMicrotome knive having an edge which is necessarily very sharp.Heretofore, after'such a knife had been used for a short period of time,the edge would become dulled and a perfect cut could not be made, andthe knife would have to be sent to an expert grinder who would regrindand hone the edge.

The instant device is adapted to enable the resharpening of these knivesby the operator, without necessitating the same being sent to a grinder.The strop 31 i usually one adapted to be used for initial sharpening,and is preferably made of pig skin which is impregnated with an abrasivedust, such as diamond dust or any other suitable abrasive material whichis adapted to cut a hardened surface. The strop 38 is usually afinishing or shell strop, and is made from a finer grade of hide,usually being out from the hind portion thereof.

To make a clean out which will leave no marks on the surface of theslice, a uniform and even cutting edge must be had. To produce such anedge the knife is preferably first properly honed, and is then sharpenedon the strop 31. The strop 31 produces a plurality of fine lines in thesurface of the cutting edge which makes the same ideal for cutting. Thelock nut 24 i then loosened, the unit I 5 rotated upon the stand II tobring the strop 38 into operative position, and the lock nut 24tightened to retain the unit IS in such position. The knife edge is thenfinished on the strop 38, whereby the lines, which were formed in thesurface thereof by the strop 31, will be smoothed and straightened, sothat when a specimen is cut a smooth surface will be assured.

While the device is preferably adapted to be used for Microtome knivesor laboratory knives, it will be apparent that it is also adapted to beused on other sharp cutting implements, such as razors or the like.

From the above description, it will be seen that a device is providedupon which a pair of strops are mounted which may be selectivelytensioned to any desired degree without applying undue strains orstresses to the device, and which will maintain the tension uniform uponboth of the strops. At the same time, the tensioning u it forming partof the device may be selectively a justed to bring a desired strop intooperati e position, and may be locked in such position, thereby enablingthe operator to use both hands in guiding the knife, rather thannecessitating the tiring and inefficient method of holding the stroptaut with one hand while stropping. It will also be apparent thatprovision may readily be made for the mounting of two additional strops,if desired, upon the unoccupied sides of the tensioning unit I5.

It is thought that the invention and many of its attendant advantageswill be understood from the foregoing description, and it will beapparent that various changes may be made in the form, construction andarrangement of the parts without departing from the spirit and scope ofthe invention or sacrificing all of its material advantages, the formhereinbefore described being merely a preferred embodiment thereof.

I claim:

1. In a device of the class described, a stand portion, and a tensioningunit mounted upon said stand portion, comprising a plurality of strops,a pair of interengaging members for removably supporting said strops,means for moving said members relative to each other to apply a desireddegree of tension to said strops, means mounting said tensioning unitfor rotation upon said stand portion to enable the positioning of aselected strop in operative position, and threaded locking meanscooperating with said mounting means for rigidly locking said tensioningunit in any desired position against rotation upon and relative to saidstand portion.

2. A mounting for a plurality of strops, comprising a stand portion, afirst member, a first stud joined to and rotatably supporting said firstmember upon said stand portion, a second member slidably engagable withsaid first member for movement relative thereto, a second stud forsupporting said second memberon said stand portion for rotation withsaid first member and operable to impart sliding movement to said secondmember relative to said first member, said members being provided withmeans for removably engaging opposite ends of a plurality of strops,whereby sliding movement of said members relative to each other willapply a desired degree of tension to said strops and rotation of saidmembers relative to said stand portion will enable the positioning of aselected strop in operative position, and wing nuts respectivelyengaging said studs for locking said member and 1said strops as a unitin any desired selected posi- EDWARD J. DOHNAL.

